micro lab exam 2 reported questions well answered.

The reagent that must be added to the starch agar plate to confirm hydrolysis is - correct answers Iodine The enzyme that catalyzes the conversion in starch hydrolysis is - correct answers Amylase what color should the starch agar plate become ( after the addition of iodine) if the organism is starch hydrolysis - correct answers negative _ dark positive _ clear what is the indicator used in carbohydrate fermentation test? - correct answers Phenol Red what is the purpose of the Durham tube inside this carbohydrate fermentation test? - correct answers To collect gas what is the carbohydrate fermentation test, test for? - correct answers... what is the name of the tube to detect gas production from fermentation - correct answers Durham A differential test medium which is used to differentiate members of Enterobacteriaceae and to distinguish them from other gram negative rods are - correct answers oxidase test In phenol red broth, what lowers the pH? - correct answers acid byproducts what test is designed for organisms that are able to ferment glucose, but quickly convert their acid products to acetoin and 2,3-butanediol - correct answers MRVP what is a positive VP result? - correct answers If the culture is positive for acetoin, it will turn the upper part of tube the color red or pink. and pH is below 4.4 A Voges-Proskauver positive organism converts glucose to - correct answersAcetoin Before you add reagent to MR or VP tubes, or record results for PR broths, what must you be sure has occurred? - correct answersbroth What reagents are used to Voges-Prokauer test? - correct answersMethyl Red indictor Give three examples of aseptic technique used in the microbiology laboratory? - correct answersFlaming, washing, sterilizing What are you trying to achieve by doing a streak plate ( correctly)? - correct answersTo isolate and grow bacteria from some type of sample what does a streak plate enable you to observe by looking at the bacteria growing on a slant or in a broth - correct answers... why do you incubate and store your culture plates upside down (inverted)? - correct answersso that condensation does not drip onto the plate and interfere with the devleloping microbes Why are agar plates better than slants. - correct answersyou can see individual colonies to analyze colony morphology. you also can see elevation. slants are more crowed and are use for a short period of time why are slants better than agar plates? - correct answersthey can be stored easier and do not take up much space. Slants can also be used to determine motility of bacteria UV light causes _______ to form in the DNA of bacteria exposed to UV light - correct answersadjacent thymine bases How would you expect spore formation to affect the survival of bacteria exposed to UV light? - correct answersUv does not cause death to endospores because they have protein around the DNA that provide protection from the damaging affects of UV mutagens - correct answersagents such as UV radiation that cause high rates of mutation what enzymes repair UV DNA mutation in visible light - correct answersphotolyases give example of where UV radiation might be used as a sterilizing agent - correct answersHospitals operating rooms, food processing areas and wastewater bactericidal agents - correct answersresult in bacterial death which is generally more sensitive to disinfectants / antiseptics, organisms in exponential growth, or those in the stationary phase. - correct answersThe stationary phase would have the best survival after exposure to UV because many of the bacterium would of formed endospores Name the agar that is used in the Kirby-Bauer test. why is this specific agar used? - correct answersMueller Hinton. it is throughly tested for its composition and its pH level. its also ensures that zone of inhibitation can be reproduced from the same organism A clear Zone of no microbial growth around a disc on an agar plate is - correct answerssusceptible What test would you do and how would you interpret the results to make a confirmed diagnosis of staphylococcus aureus given a gram positive coccus? (miminium 3 tests) - correct answers... A yellow color on a mannitol salt agar plate indicates - correct answers the production of acid end products What is the selective agent for Mannitol salt agar - correct answers7.5 % NaCl What is the indicator for Mannitol salt agar? - correct answers phenol red Mannitol salt agar allows the growth of - correct answers Grave Positive organism